fix(recovery): let preservation owners reopen retained sources (#17053)

## Thinking Path

> - Paperclip is the open source app people use to manage AI agents for
work.
> - Recovery must save retained workspace files before ordinary
execution can resume.
> - The environment runtime blocks access to retained sources to prevent
unsafe reuse or deletion.
> - The recovery worker also used that ordinary resume path.
> - The guard returned no lease, so recovery reported an invalid source
binding before it could save files.
> - This pull request gives the physical preservation owner a separate,
source-bound resume path.
> - Ordinary execution and destructive cleanup keep their existing
guards.

## Linked Issues or Issue Description

Refs #16965.

**What happened?**

A retained workspace with a workspaceRestoreRecovery marker could not
recover through the real environment runtime. The runtime returned null
before calling the provider. Recovery classified this as
source_binding_invalid. Earlier recovery fixtures replaced the runtime
facade, so they did not exercise this guard.

**Expected behavior**

The verified preservation owner can reopen its exact stopped allocation
to save files. Other callers remain blocked. Recovery preserves newer
local files and does not start another agent or repeat a completed
external action.

**Steps to reproduce**

1. Seed a terminal source run with a retained sandbox, a recovery
action, and the workspaceRestoreRecovery lease marker.
2. Give the source a verified stop receipt.
3. Call recoverRetainedWorkspace through environmentRuntimeService.
4. Before this change, the recovery action returns to blocked with
source_binding_invalid. No files are copied.

**Paperclip version or commit**

Reproduced on master at 65f59e339a. The
same failure was observed in a served build containing #16965.

## What Changed

- Add an internal preservation resume method. It validates the exact
company, task, run, action, lease, environment, current physical owner,
and stop-only cleanup claim before provider access.
- Keep ordinary resume and destructive cleanup blocked for protected
sources.
- Run all retained-workspace fixtures through the assembled environment
runtime. Add a failing-before/passing-after protected-source regression
and four rejection cases.
- Use the same runtime path and protection marker in the opt-in Daytona
interruption probe. Allow a verified immutable snapshot UUID as its
input.
- Document the authority boundary and verification recipes.

## Verification

- Red: the protected-source regression failed with expected recovered,
received blocked. It recorded source_binding_invalid before provider
resume.
- Green: 235 tests passed across workspace recovery, durable task Retry,
and environment runtime. These include saved files, newer local files,
bounded retries, competing owners, and no extra run or wake.
- pnpm -r typecheck and pnpm build passed. The initial sandboxed
typecheck could not open a tsx IPC pipe; the same command passed with
local process access.
- node scripts/check-maps.mjs and git diff --check passed.
- Live Daytona qualification passed using the same immutable snapshot ID
as the affected deployment. Export was interrupted after a real
download; a second controller restored the files and verified one
original agent start, one simulated external action, one saved snapshot,
and a stopped retained source. The disposable sandbox was deleted after
verification.
- Greptile reviewed 804dfe24ef at 5/5 with
no actionable findings or unresolved review threads.
- Full current-commit CI passed:
https://github.com/paperclipai/paperclip/actions/runs/39540771747.
Required ci / verify and ci / e2e passed. Superagent, Socket, and Snyk
checks passed.
- Full local pnpm test:run did not pass: 22,992 tests passed, one
managed-run identity test timed out at 60 seconds, and 100 tests skipped
across the first general-server phase. The command stopped before its
later phases. The unchanged agent-identity.test.ts suite then passed all
11 tests in isolation in 15.53 seconds. The original timeout remains
recorded; it is not reclassified as a full local pass. The same commit's
complete CI test matrix passed.
- The optional Paperclip Review completed with a neutral advisory 5/5 on
the same head and no actionable findings. It inspected all eight changed
files and connected code. It did not independently run tests or the
provider probe.
- Hosted ordinary Retry recorded one durable intent and no successor run
while file preservation remained blocked. The existing published review
stayed unchanged. Hosted recovery remains unverified until this
follow-up is deployed. A Retry acknowledgement alone does not prove
recovery.

## Risks

- Recovery can reopen a retained sandbox. The dedicated path requires
the current physical ownership claim and the exact source's stop-only
intent. It does not clear the ordinary protection marker.
- Provider failures retain the source and use the existing bounded
recovery budget. The provider cannot substitute another allocation.
- The live probe uses a disposable sandbox and simulated
agent/external-effect counters. It does not prove a live LLM or GitHub
review journey.
- No schema, public API, permission, budget, pause, or approval changes.

## Model Used

OpenAI GPT-6 through Codex, with repository inspection, code execution,
browser verification, and test tools. The exact served model variant and
context window are not exposed by this session.

## Checklist

- [x] I have included a thinking path that traces from project context
to this change
- [x] I have specified the model used (with version and capability
details)
- [x] I have checked ROADMAP.md and confirmed this PR does not duplicate
planned core work
- [x] I have searched GitHub for duplicate or related PRs and linked
them above
- [x] I have either (a) linked existing issues with `Fixes: #` / `Closes
#` / `Refs #` OR (b) described the issue in-PR following the relevant
issue template
- [x] I have not referenced internal/instance-local Paperclip issues or
links (only public GitHub `#NNN` / `github.com/paperclipai/paperclip`
URLs)
- [x] My branch name describes the change (e.g. `docs/...`, `fix/...`)
and contains no internal Paperclip ticket id or instance-derived details
- [x] I have run tests locally and they pass (focused suites; full suite
still running)
- [x] I have added or updated tests where applicable
- [x] I have updated relevant documentation to reflect my changes
- [x] I have considered and documented any risks above
- [x] All Paperclip CI gates are green
- [x] Greptile is 5/5 with no open P2s, recommendations, or follow-ups
- [x] I will address all Greptile and reviewer comments before
requesting merge

---------

Co-authored-by: Paperclip <noreply@paperclip.ing>

doc/task-recovery.md

@@ -33,6 +33,12 @@ The source recovery action holds a validated `systemRecovery` record. Its
 revision and generation fence late bookkeeping writes. Physical exports still
 use the existing workspace ownership lock and controller stop receipts.
 
+The export owner can reopen its exact stopped sandbox through the environment
+runtime's recovery path. This path checks the current source action, run,
+environment, allocation, stop-only intent, and physical ownership claim before
+calling the provider. The retained-source fence still blocks ordinary resume
+and destruction. Recovery does not clear it to gain access to the saved files.
+
 Execution containment and file preservation are independent facts:
 
 - Another agent needs authoritative containment of the old executor.
@@ -113,6 +119,8 @@ Run the focused PostgreSQL/filesystem suites from `server/`:
 `server/scripts/workspace-recovery-provider.test.mjs` is an opt-in controlled
 Daytona probe. It requires `PAPERCLIP_RECOVERY_LIVE=1`, `DAYTONA_API_KEY`,
 `PAPERCLIP_DAYTONA_SDK_PATH` and an immutable `PAPERCLIP_RECOVERY_IMAGE`.
+An immutable provider snapshot UUID in `PAPERCLIP_RECOVERY_SNAPSHOT_ID` can
+replace the image digest. The probe checks its ID and active state first.
 It interrupts export,
 joins the first controller, starts a second controller and verifies files,
 preservation receipts, agent-start count and external-operation count before